The present invention relates to a swing clamp apparatus in which the clamp arm is reciprocated and swung.
Conventionally, the swing clamp apparatus comprises a clamp body, a clamp rod, a clamp arm, and a drive mechanism. The clamp rod is inserted in and supported by the clamp body reciprocally in the axial direction and rotatably about the axis. The clamp arm is fixed to the leading end of the clamp rod. The drive mechanism is provided in the clamp body to reciprocate and rotate the clamp rod so as to switch the clamp arm between an unclamping position and a clamping position where the clamp arm is retracted in the axial direction and swung about the axis in relation to the unclamping position.
In the above swing clamp apparatus, the clamp arm may be replaced with different ones in size or shape when a clamping object is changed. Usually the clamp arm is directly fixed to the clamp rod by bolts. For example, in the clamp apparatus of Patent Document 1, the clamp arm has an axial bore in which the leading end of the clamp rod is inserted and a slit continued from the axial bore. A bolt is inserted in the clamp arm through the slit so that the bolt fastens and directly secures the clamp arm to the clamp rod.
The clamp arm reciprocates and swings in the swing clamp apparatus. Therefore, the clamp arm has to be positioned and fixed to the clamp rod at a desired position for reliably clamping and unclamping a clamping object.    Patent Document 1: U.S. Pat. No. 5,192,063 Publication